fix: add packages write permission for Docker image push to GHCR

The build job was failing with:
'denied: installation not allowed to Create organization package'

Added required permissions to build job:
- packages: write (for pushing to GitHub Container Registry)
- contents: read
- id-token: write

This allows the workflow to push Docker images to ghcr.io/zie619/n8n-workflows

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/ci-cd.yml

@@ -120,6 +120,10 @@ jobs:
     runs-on: ubuntu-latest
     needs: [test, security]
     if: github.event_name != 'pull_request'
+    permissions:
+      contents: read
+      packages: write
+      id-token: write
 
     steps:
     - name: Checkout code